People just keep figuring out that things we did in Smalltalk a long time ago have merit:

SecondLife is using Mono in a non-conventional way, which I like to think is one of the benefits of having an open source engine, they have added a micro-threading implementation.

Microthreading was necessary because some of their simulations are made up of thousand of threads/routines, and using the default threads in Mono (which are mapped to operating system threads) would have been too heavy.

That's why BottomFeeder can spawn a thread per feed, even when subscribed to hundreds of feeds - because they don't map down to OS threads.